Kenya's more than 4,000 death row inmates all will have their sentences commuted to life imprisonment, the president announced Monday, describing their wait to face execution as "undue mental anguish and suffering."

No death sentence has been carried out in the past 22 years in the East African nation. President Mwai Kibaki said he made the decision following advice of a constitutional committee and that he was commuting the sentences using powers provided for under Kenya's constitution.

"Extended stay on death row causes undue mental anguish and suffering, psychological trauma (and) anxiety while it may as well constitute inhuman treatment," the president said in a statement.

"It's been a long time coming," Wanyeki told The Associated Press. Her organization has been campaigning for years for reforms in Kenya's prisons as well as repealing the death penalty from the country's law books.

Wanyeki said that the death penalty is a mandatory sentence in Kenya for anyone convicted of armed robbery or murder.

Kibaki said he has directed government officials to study whether the death penalty has any impact on fighting crime. He also appealed to Kenyans to promote a national debate on the issue, suggesting the government may be preparing the ground for a repeal of the death penalty.

Attorney General Amos Wako has in the past advocated repealing the death penalty. That would require a vote in parliament, where such a move has faced strong opposition.

"In a way, this may be unpopular with a section of the public," Wanyeki said.

Kenya's 97 prisons are overcrowded, underfunded and understaffed. They were built for a population of about 15,000 but have an inmate population of more than 40,000.